Mechanical Influence of Edentulous Mandibular Morphology on Peri-implant Bone in Implant Prosthetics: Threedimensional Finite Element Analysis.

PURPOSE: The purpose of this study was to examine the mechanical influence of edentulous mandibular morphology on peri-implant bone in implant prosthetics by finite element analysis. MATERIALS AND METHODS: Computed tomographic data from 25 patients with edentulous mandibles were selected and the radius of mandibular curvature and the height of the mandible at the midline were measured in order to clarify the morphological characteristics of the mandible. From the measurement, two patients with the smallest and largest radii of the mandible were selected. Two types of three-dimensional finite element models consisting of the edentulous mandible (small and large radius), superstructure (a cantilever bridge), implants, and abutments were created. Four implants were inserted between the right and left mental foramina. The upper surface of the mandibular condyle was constrained, and a vertical load of 100 N was applied on the occlusal surface of the right first molar. Three-dimensional finite element analysis of each model was performed to examine the mechanical influence of the edentulous mandibular morphology on the peri-implant bone. RESULTS: Measurement of mandibular morphology in CT images indicated that the lower the mandibular height was, the larger was the radius of the anterior mandibular curvature. Finite element analysis revealed that a higher equivalent stress was generated in the peri-implant bone of the model with a larger radius of curvature than that of the model with a smaller radius of curvature. The highest equivalent stress in the mandible was generated in the distal margin of the peri-implant bone posterior to the loaded side of the large radius of curvature model. CONCLUSIONS: The mandibular morphology had a mechanical influence on the peri-implant bone.

Effect of Continuous Box-trainer Training on Laparoscopic Skills of Surgical Residents: A Prospective, Observational Study.

BACKGROUND/AIM: As opportunities for hands-on surgical training during residency have decreased, off-the-job training before surgery is gaining importance. We developed a training program using a box-trainer for surgical residents. This study aimed to verify the effectiveness of the program. Using task-achievement time, we demonstrated the learning curve through continuous task training and verified the efficiency of our training tasks. In addition, we examined the circularity of the cut circle to evaluate the task accuracy and summarized the questionnaire results. PATIENTS AND METHODS: A prospective, observational study was conducted at a single center with five trainees from April 2019 to March 2020. The training consisted of four tasks based on the Fundamentals of Laparoscopic Surgery module. The trainees had to achieve expert proficiency time targets. The task-achievement time and circularity of the cut circle were used for objective assessment; subjective evaluation was done using a questionnaire. RESULTS: Although the learning curves of the task-achievement time seemed to reach a plateau between the third and the fifth skills lab, all the trainees achieved expert proficiency times for the three tasks. Circularity of the cut circle tended to be more accurate after training. All trainees perceived an improvement in their skills after the training program. The level of satisfaction of the training program was rated as 'very satisfied' or 'satisfied'. CONCLUSION: Continuous box-trainer training for 1 year may be effective for improvement in preoperative laparoscopic surgical skills of surgical residents.

Laparoscopic repair of inguinal hernia in a patient with a ventriculoperitoneal shunt: A case report.

Laparoscopic surgery in patients with a ventriculoperitoneal (VP) shunt is reportedly associated with increased intracranial pressure secondary to high intraperitoneal pressure and retrograde infection due to intraperitoneal infection. We herein report the first case of transabdominal preperitoneal (TAPP) inguinal hernia repair without catheter manipulation for a patient with a VP shunt. A 69-year-old man with a VP shunt was suspected to have an inguinal hernia based on symptoms and examination findings. With a pneumoperitoneum pressure of 10 mm Hg, the VP shunt was not clamped and mesh was placed while confirming cerebrospinal fluid outflow from the tip of the catheter. The patient developed no shunt-associated complications and was discharged 3 days postoperatively. TAPP inguinal hernia repair without catheter manipulation is a potential surgical option for patients with a VP shunt.